Strap tension buckle



Jun 3, 1969 J. R. BEACH 3,447,208

STRAP TENSION BUCKLE Filed Sept. 22, 1967 fizuerz @ZWMZ? $0M United States Patent U.S. Cl. 24-23 11 Claims ABSTRACT OF THE DISCLOSURE A tension buckle of molded nylon in the shape of a fiat E-frame is disclosed for symmetrical bridging connection between adjacent ends of packaging strap. The E-shape disclosed herein includes a main endwise run carrying endmost cantilever arms or crossbars terminating in enlarged free ends and a center arm of U-shape to present intermediate crossbars joined by an endwise run portion. The endmost crossbars are larger in transverse section than the intermediate crossbars and are carried by portions of the main endwise run that are of maximum transverse section for increased resistance to bending. Each endmost crossbar and adjacent intermediate crossbar form a crossbar set to receive a strap end in a reverse fold configuration wherein a strap bight portion embraces the endmost crossbar and buckle-gripping and overlapping strap-gripping strap portions lead between the intermediate crossbars and then endwise beyond the strap bight portion.

Background of the invention The invention relates to tension buckles for securing adjacent ends of flexible packaging strap and, more particularly, is concerned with a buckle for use with nonmetallic strap, for example, an oriented nylon or polypropylene plastic, for securing opposite ends of a strap loop which is to be arranged in taut relation about a package.

Since metal seals which require mechanical crimping have found somewhat limited application with plastic strap, numerous types of buckles have been devised which depend upon development of mechanical frictional engagement with the strap ends. In the case of some prior art buckles, the gripping action at one end has been greater than at the other due to a lack of symmetry in the buckle configuration. In addition, the prior art buckles have frequently required special tools and have generally not satisfied the diverse conditions of being easy to thread and tension while exerting a high snubbing force. Finally, the prior art buckles have exhibited an irregular profile and project from the package to present an objectionable bump.

Summary of the invention In accordance with this invention, a tension buckle is provided in the form of a rigid, one-piece planar skeletal frame that provides symmetrical engagement with the strap ends to enable equalized directional holding. The buckle lies fiat against the package being strapped and it can face in either direction.

The tension buckle has a main endwise run carrying four generally parallel crossbars that constitute a pair of crossbar sets, each set to receive a strap end in an identical fashion wherein the strap end has a reverse fold configuration defining a strap bight portion engageable about an endmost buckle crossbar, the bight portion integrally joining a buckle-gripping strap portion and an overlapping strap-gripping strap portion that lead between the intermediate crossbars and then endwise beyond the strap bight portion.

In the disclosed embodiment, the buckle frame is of generally E-shaped plan outline wherein the arms at op- "ice posite ends of the main endwise run provide cantilever endmost crossbars and wherein a central U-shaped arm provides spaced intermediate crossbars integrally connected by an endwise run portion. Each endmost crossbar has an enlarged remote end presenting an abutment stop to retain the strap on the buckle. The portions of the main endwise run that carry the cantilever crossbars are of maximum transverse section and the intermediate crossbars which receive overlapping strap portions are smaller in transverse section than the cantilever crossbars.

The buckle of this invention is easy to thread and pull slack through and under tension is able to exert a snubbing force equalized in both directions and approaching the actual strength of the strap. The unique configuration of the buckle permits use of molded plastic while still achieving effective strap gripping whereas many prior art buckles require steel either for strength or for grip characteristics or both.

Other features and advantages of the invention will be apparent from the following description and claims, and are illustrated in the accompanying drawings which show structure embodying features of the present invention and the principles thereof.

Brief description of the drawings In the accompanying drawings forming a part of the specification, and in which like numerals are employed to designate like parts throughout the same,

FIG. 1 is a perspective view illustrating a package tied with a strap loop, the opposite ends of which are secured by a tension buckle in accordance with the present invention;

FIG. 2 is an enlarged plan view of the buckle;

FIG. 3 is an enlarged fragmentary lengthwise sectional view taken through a buckle at the plane indicated by the line 33 of FIG. 2, the buckle being shown with opposite ends of the strap threaded therein;

FIG. 4 is a transverse section taken on the line 4-4 of FIG. 2;

FIG. 5 is a transverse section taken on the line 55 of FIG. 2; and

FIG. 6 is a reduced fragmentary lengthwise sectional view generally similar to FIG. 3 and showing a crossbar sectional profile used in another embodiment of the invention.

Description of preferred embodiment Referring now to the drawings, a typical application in which the buckle of the present invention is employed is illustrated in FIG. 1 wherein a package or other object that is to be tied is designated generally at 10 and is shown equipped with a loop of strap 11 having its opposite end portions 12, 13 individually threaded through opposite ends of the buckle B. The buckle is seen to serve as a bridging connection for holding tension on the loop of the strap, with the buckle being symmetrical and having symmetrical engagement with the strap ends to establish equalized directional holding power.

Strap buckles have found wider use with the advent of oriented, long-chain thermoplastic strapping such as nylon or polypropylene. Buckles of bent Wire have been used but they are not symmetrical and do not achieve equalized holding power. The magnitude of the snubbing force between the strap :and the buckle depends upon the threaded configuration of the strap end in the buckle and this in turn depends upon the buckle crossbar configuration at each end of the buckle.

The buckle shown herein for purposes of illustrative disclosure is generally E-shaped in plan outline as is best seen in FIG. 2, the buckle being comprised of a rigid, one-piece, planar skeletal frame having a main endwise run 14 defining one lateral extremity of the E and carrying four endwise spaced crossbars projecting in generally parallel relation from a common side of the endwise run to define a set of crossbars 15, 16 at one end of the buckle for strap end 12 and a set of crossbars 17, 18 at the other end of the buckle for strap end 13.

In the disclosed E-shape, the endmost arms of the E provide cantilever endmost crossbars 15, 17 projecting in generally parallel relation at opposite extremities of the E and a central U-shaped arm of the B provides the endwise spaced intermediate crossbars 16, 18 which are connected at their remote ends by an endwise run portion 19.

The crossbar set 15, 16 receives strap end 12 in a reverse fold configuration that is identical to the manner in which the crossbar set 17, 18 receives strap end 13 so that the snubbing force is directionally equalized and the buckle and strap connections are truly symmetrical. These relationships exist for all positions of the buckle so that the buckle may be threaded from either end or either side in accordance with the convenience of the user.

In the particular reverse fold strap configuration shown herein, each strap end is folded to provide a bucklegripping strap portion 20 and an overlapping strap-gripping strap portion 21. Each buckle-gripping portion 20 is adjacent the free end of the strap and is integrally joined to the strap-gripping portion 21 by an intermediate strap bight portion 22. To thread the strap through the buckle, the leading portion of the folded strap end 12 is fed upwardly through the central space defined by the U-shaped arm sufiiciently to provide slack to allow the strap bight portion 22 to be inserted laterally upon the cantilever crossbar 15. The strap is encircled about the package 10 and the other end is provided with a reverse fold to feed through the same central space until its strap bight portion 22 can be inserted laterally to embrace the cantilever crossbar 17. It may be noted that the lateral opening between each crossbar set facilitates the loading operation.

Tension is drawn by pulling slack strap through either end of the buckle. An important feature of the symmetrical buckle configuration is that the slack strap can easily be drawn through the buckle for tensioning the loop whereas the buckle is capable of developing a snubbing force against strap withdrawal that closely approaches the actual strength of the strap. This snubbing force depends upon the relationship between each strap end and the corresponding crossbar set and it is developed principally between the frictionally contacting regions of the strap portions 20 and 21 that lead around the intermediate crossbars 16, 18. This snubbing effect is maximized by the high range of contact established against the strap as a result of the fiat profile that characterizes the present symmetrical buckle. This flat profile is apparent in FIGS. 1 and 3. Thus, the buckle surfaces need not be rough or slipproof so that a wide choice of buckle materials are suitable. For examples, injection molded plastic such as nylon, or die cast zinc or even metal stampings may be employed where disposal of scrap metal is not a problem.

In the embodiment illustrated in FIGS. 1 to 5, each cantilever crossbar 15, 17 has an enlarged free end portion 15E, 17E, respectively, presenting an abutment shoulder to retain the strap against lateral slippage by edge engagement with the strap bight portions 22. The intermediate endwise run 19 that joins the intermediate crossbars also precludes lateral escape of the strap. A buckle of injection molded nylon for use with inch thermoplastic strap of 0.014 inch thickness is shown in true proportion in FIGS. 2 to 5. This buckle is about 1 inch by inch in plan outline and has intermediate crossbars 16, 18 of A; inch diameter, cantilever crossbars 15, 17 of inch diameter and strap retaining shoulders at 15B and 17E that project endwise about 0.020 inch. The portions of the main endwise run 14 that connect the intermediate crossbar with an adjacent cantilever crossbar is of maximum transverse section to provide maximum resistance to bending, thereby tending to maintain the crossbars transverse to the strap. The central portion of the main run is shown to FIG. 4 and has a pair of lengthwise extending recesses bordering and defining an exterior rib which is particularly adapted to receive identification indicia.

Another embodiment of a tension buckle is illustrated in section in FIG. 6 wherein each of the crossbars 15', 16', 17' and 18 has a teardrop cross sectional shape. Each set of crossbars 15', 16' and 17', 18' have the tapered regions in confronting relation so that the strap bearing regions are rounded and wider for a given buckle size to promote increased resistance to bending due to strap tension.

What is claimed is:

1. In combination, a tension buckle, a packaging strap having opposite ends adjacent one another, each strap end having a reverse fold configuration to define a strap bight portion integrally joining a buckle-gripping portion and an overlapping strap-gripping portion, each bucklegripping portion being a free strap end, said buckle being a rigid, one-piece, planar skeletal frame of generally E- shaped plan outline having a main endwise run carrying end arms providing cantilever crossbars projecting in generally parallel relation at opposite extremities thereof and carrying a central U-shaped arm providing spaced intermediate crossbars, one for each cantilever crossbar and generally parallel thereto, and an endwise run portion joining remote ends of said intermediate crossbars, each cantilever crossbar and adjacent intermediate crossbar defining a crossbar set for receiving a corresponding strap end in reverse fold configuration, the strap bight portion of each strap end embracing an endmost crossbar, the overlapping strap-gripping portions, leading around the intermediate crossbars, and the buckle-gripping portions extending between an endmost crossbar and an intermediate crossbar beneath an overlapping strap-gripping portion and then endwise beyond the strap bight portion.

2. A tension buckle in accordance with claim 1 wherein each cantilever crossbar has an enlarged free end portion presenting an abutment shoulder to retain strap on said buckle.

3. A tension buckle in accordance with claim 1 wherein each intermediate crossbar is of smaller transverse section than the corresponding cantilever crossbar.

4. A tension buckle in accordance with claim 1 wherein said frame is of molded plastic and has portions of maximum transverse section between each of said cantilever crossbars and the adjacent intermediate crossbar.

5. In combination, a tension buckle, a packaging strap having opposite ends adjacent one another, each strap end having a reverse fold configuration to define a strap bight portion integrally joining a buckle-gripping portion and an overlapping strap-gripping portion, each bucklegripping portion being a free strap end, said buckle being a rigid, one-piece, planar skeletal frame having an endwise run along one lateral extremity thereof and carrying four endwise spaced crossbars projecting in generally parallel relation from a common side of said endwise run, each endmost crossbar cooperating with each adjacent intermediate crossbar to define a crossbar set for receiving each strap end in reverse fold configuration, the strap bight portion of each strap end embracing an endmost crossbar, the overlapping strap-gripping portions leading around the intermediate crossbars, and the buckle-gripping portions extending between an endmost crossbar and an intermediate crossbar beneath an overlapping strapgripping portion and then endwise beyond the strap bight portion.

6. A tension buckle in accordance with claim 5 wherein said endmost crossbars have endwise projecting portions at ends thereof remote from said endwise run to retain the strap on said buckle.

7. A tension buckle in accordance with claim Wherein said endmost crossbars have endwise projecting portions at ends thereof remote from said endwise run to retain the strap on said buckle and wherein said intermediate crossbars have an endwise run integrally joining ends thereof remote from said endwise run.

8. A tension buckle in accordance with claim 5 wherein said intermediate crossbars are smaller in transverse section than said endmost crossbars.

9. A tension buckle in accordance with claim 5 Wherein said endwise run has portions between each of said endmost crossbars and the adjacent intermediate crossbar is of greater transverse section than the portion between said intermediate crossbars.

10. A tension buckle in accordance with claim 5 wherein said frame is of molded plastic and has portions of maximum transverse section between each of said endmost crossbars and the adjacent intermediate crossbars and wherein said intermediate crossbars have an endwise run joining ends thereof remote from the first-named endwise run.

11. In combination, a tension buckle, :a packaging strap having opposite ends adjacent one another, each strap end having a reverse fold configuration to define a strap bight portion integrally joining a buckle-gripping portion and an overlapping strap-gripping portion, each buckle-gripping portion being a free strap end, said buckle including four spaced, generally parallel crossbars, the

longitudinal axis of said crossbars being disposed in a common plane, each endmost crossbar cooperating with each adjacent intermediate crossbar to define a crossbar set for receiving each strap end in reverse fold configuration, the strap bight portion of each strap end embracing an endmost crossbar, the overlapping strap-gripping portions leading around the intermediate crossbars, and the buckle-gripping portions extending between an endmost crossbar and an intermediate crossbar beneath an overlapping strap-gripping portion and then endwise beyond the strap bight portion.

References Cited UNITED STATES PATENTS D. 25,563 6/1896 Mueller.

70,452 11/ 1867 Merritt 2422 178,762 6/ 1876 Goldsmith.

285,048 9/ 1883 Liljencrantz 24200 XR 686,129 l1/1901 Ragsdale et a1. 2426 2,099,199 11/1937 Devendor et al 24198 FOREIGN PATENTS 225,945 12/ 1959 Australia.

961,738 11/ 1949 France.

450,772 8/ 1949 Italy.

DONALD A. GRIFFIN, Primary Examiner. 

